Projectile



H' F' DUNLAP ET AL Oct. 24

PROJECTILE 4 Sheets sheet 2 Filed June 50, 1944 INVENTORS:

BY ARLES E. HA LUI-EL ATT NEY H. F. DUNLAP ETAL Oct. 24, 1961 4 Sheets-Sheet 5 lNvENToRs HEWR YE DUN/ AP BY CHARLE S E' HABLU TZE L Aondm Oct. 24, 1961 H. F. DUNLAP ETAL 3,005,409

PROJECTILE Filed June 30, 1944 4 Sheets-Sheet 4 INvENToRs HENRY l." DUNL AP ATTORNEY OHARL S HABLUTZEL Staes 3,005,409 PROJECTILE Henry F. Dunlap and Charles E. Hablutzel, Albuquerque,

N. Mex., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed June 30, 1944, Ser. No. 543,006 3 Claims. (Cl. 102-93) thereto, and a sleeve-like bourrelet made of relatively light-weight material, such as plastic, mounted on the core in front of the sabot with the rear end of the bourl atCIl FIG. 9 is a view similar to FIG. 6 showing a further modification of the projectile;

FIGS. 10 land l1 are cross sectional views on lines 10 10 and 11 11, respectively, in FIG. 9;

FIG. 12 is a side elevational view, partlyV in section, showing another form of the projectile;

FIG. 13 is a sectional view on the line 13 13 in FIG. 12;

FIG. 14 is a side elevational view, partly in section, of still Aanother -form of the projectile, showing the sabot and bourrelet threaded on the core;

FIG. 15 is an enlarged sectional view on the Iline 15 15 in FIG. 14;

FIG. 16 is a side elevation of another form of the sabot-projectile;

FIG. 17 is a view similar to FIG. 16 showing parts of the projectile in section, and

FIGS. 18, 19 and 20 are cross sectional views on the lines 18 18, 1-9 l19; and 20 20, respectively, in FIG. 17.

The projectile of the present invention is of the socalled sabot type in whicha subcaliber core is supported ,and centered, during its movement through a gun barrel,

relet engagetLandY supportedflgetl'teF salaetthesabot generieallyeidentined:sabeeandetanaingb andY i i i bourrelet being releasable from the core by centrifugal 25 assembly, Iand a bourrelet which are discardable automatiforce incident to rotation of the projectile as it emerges from the gun barrel.

A further object of the invention is to provide a sabotprojectile having a sabot and a relatively light-weight sleeve-like bourrelet mounted on a subcaliber core and in which the bourrelet is supported laterally by the sabot so that it is unnecessary to provide positive means for locating the bourrelet axially on the core.

Another object of the invention is to provide a sabotprojectile of the character described in which the bour- Yrelet has longitudinal radial cuts or recesses for providing weakened zones in the bourrelet, whereby the bourrelet is adapted to break at the weakened zones under the centrifugal force to facilitate its release from the core.

,cally under the action of centrifugal force when the projectile emerges from the gun barrel. A projectile of this type is disclosed ina copending application of C. E. Hablutzel, Serial No. 543,005, tiled lune 30, 1944, and now abandoned. In the projectile there shown, the sabot and bourrelet are relatively narrow, ring-like members positively secured to the core in longitudinally spaced relation, the bourrelet ring being mounted near the nose portion and the sabot ring being mounted near the end of the core. With this construction, it is necessary to provide means for positively securing the bourrelet :to the core to preyent it from sliding axially on the core when the projectile is red. The new projectile is characterized by a sleeve-likebourrelet of relatively light-weight material A fnl'thel' @bleot 0f the invention S '0 PIOVde a Sabot- 40 which is engaged at its rear end by the front face of the projectile of the character described in which the bourrelet and sabot are threaded on the core. v

An additional object of the invention resides in the proprojecting portion of the sabot, so that it is unnecessary to provide a positive connection between the bourrelet and the core, other than the sabot.

vision of a subcaliber projectile having a segmented nmtalfggefefg.geglgegmwtggsms pfjyprgg.

Sabot mounted 011 a SnbCJibSI COI@ and Carrying a 'lnfn- 45 5, the projectile there shown comprises a subcaliber core .ing band made of relatively light-weight material, such as plastic, which acts to hold the sabot segments together on the core, the turning band being breakable under cen- Still another object yof the invention is to provide a projectile having a subcaliber rcore, a discardable metal sabot intermediate the ends of the core for supporting a turning band, and a pair of light-weight, substantially full caliber rings itted closely` on the core, one in front and .one to the rear of the sabot, the rings serving to'support and center the'core near its ends in the gun barrel and being releasable with the sabot from the core under cen- 20 which may be made of steel, such as that used in armor-piercing projectiles, the core having an ogive.

`Mounted on the core 20 directly to the rear of the ogive is a substantially full caliber bourrelet 21 comprising a plurality of longitudinal segments 22 disposed in closely adjacent relation on the cylindrical surface of the core. The segments 22 are held together on the core by any suitable means, Such as frangible retaining rings 23 disposed in peripheral recesses in the ends of the segments.

5 .The rings 23 may be made of metal, and the segments trifugal force when the projectile emerges from the gun lines 2 2, 3 3, 4 4 and 5 5, respectively, in FIG. 1;

FIG. 6 is a side elevational View, partly in section, of a modified form of the new projectile;

FIGS. 7 and 8 are cross sectional views on the lines A7 7 and 8 8, respectively, in FIG. 6;

`2 2 are made of a light-weight material, such as plastic,

laminated phenolics, laminated lignins, plywoods bonded and impregnated with phenolics, molded phenolics with a suitable filler, wood, or the like. It will be observed Athat the bourrelet Z1 is generally sleeve-like in form and extends along the core for a substantial part of its length, the bourrelet being adapted to engage the inner wall of Vthe gun barrel to support and center the core 20 therein. While we have shown a bourrelet 21 comprisingV eight segments 22, any other desired number of segments may be employed. However, for each value of the ratio of core diameter to gun bore diameter, there is a minimum desirable number of segments, usually three or more for practicable designs. If the number of segments is less than this minimum, lateral forces may be exerted against the projectile during centrifugal release of the bourrelet,

numbers with the subscript b added. `In the projectile illustrated in FIGS. 9, and l1, however, thebourrelet sleeve 30b is prowded with configurated holes or openings 3111 extending longitudinally through the bourrelet, in place of the cuts 31. As shown, the recesses 31b are generally circular in Shape, although any other desired conguration may be employed. The longitudinal openings 31b have the function of materially decreasing the mass of the bourrelet, in addition to their function of weakening the bourrelet for centrifugal release. The openings 3117 may extend from either the inside or outside surface of the bourrelet to points approaching complete severance of the bourrelet wall. As in the preceding forms of the projectile, the bourrelet 21b is backed by engagement of its rear end with the projecting portions of the sabot segments 25b.

-In the projectile shown in FIGS. 12 and 13, a subcaliber bourrelet 35 which is preferably made of a lightweight material, as previously described. The bourrelet 3S is press fitted or otherwise mounted on the cylindrical portion of the core directly to the rear of the ogive and is made up of a single sleeve-like member. The member 3S is not segmented, as in the previous forms of the projectile, but is made of material having inherently a tensile strength suiciently small so that the bourrelet will burst under centrifugal force in the absence of weakening cuts, when the projectile emerges from the gun muzzle and is thereby released from the confining eifect of the gun barrel.

To the rear of the bourrelet 35, theV core 34 is provided with a reduced portion 36 on which a plurality of sabot segments 37 are mounted. The segments 37 project radially from the core 34 for a substantial distance and support a turning band 38 threaded on the sabot. The band 38 is made of a light-weight material, such as a plastic, and is somewhat larger in external diameter Vthan the bourrelet 35, so that therband is adapted to be engraved by the usual riing in the gun barrel to impart rotation to the projectile. The sabot segments 37 may be made of a light-weight material, such as macerated fabric, and are held together on the reduced portion 36 by the plastic turning band 38, which has lateral support on the bourrelet 35.

When the projectile is red from a gun, the bourrelet 35, the turning band 38 and the sabot segments 37 are held together on the core by the confining influence of the gun barrel as the projectile moves through the barrel, against the centrifugal force due to rotation of the projectile by action of the riing on band 38. However, when the projectile emerges from the gun muzzle and is thereby released from the confining inuence of the gun barrel, the bourrelet 35 and turning band 38 break under the centrifugal force, whereby the bourrelet, sabot and band are released from the core.

By employing a bourrelet, a sabot and a turning band made of a plastic or other light-weight material, as described, the ratio of the mass of these parts to that of the core 34 is maintained relatively low, which is a desirable feature in projectiles of this type. While we have shown the plastic turning band 38 threaded on the plastic sabot segments 37, it will be understood that the band may be made integral with the sabot. That is, the sabot and the turning band may be made of plastic or other light-weight material in a single piece which may be weakened by radial cuts partially segmenting the piece for centrifugal release. Alternatively, the light-weight material from which the sabot and turning band unit is made may have a tensile strength suiciently small so that the unit will burst under centrifugal force in the absence of weakening cuts, when the projectile emerges from the gun muzzle. Also, the bourrelet 35, sabot 37 and turning band 38 may be made in a single integral piece and may be made of a plastic lled with laminated material so that it has a suiliciently low tensile strength across certain planes to cause `it to burst `under centrifugal force in the absence' of weakening cuts, lwhen the projectile emerges from the. gun barrel.

The projectile shown in FIGS. 14 and I15 comprisesa subcaliber core 40 made of steel and having its cylindrical portion externally threaded, as shown at 40a. A substantially full caliber bourrelet 41, made of a plastic or otherlight-weight material, is threaded on the cylindrical portion 40a of the core and is disposed directly to the rear of the ogive portion of the core. The bourrelet 41 is provided with longitudinal cuts 41a radiating from its internal diameter and terminating short of its external diameter so that the bourrelet has weakened outer portions adapted to fracture under centrifugal force and thereby facilitate release of the bourrelet. A light-weight sabot 42, which may be made of macerated fabric, is threaded on the rear end portion of the core and tightened against the Jrea'iend of bourreletY 41. LThe'sabt 4Z is provided with longitudinal cuts radiating from its inner diameter so as to partially segment the sabot, the cuts being iilled with a iiber filling 43. The lling 43 is packed tightly in the radial cuts so as to seal the sabot against leakage of gas from the powder combustion, and Valso to stilen and strengthen the sabot and prevent distortion of the sabot upon transmission of torque. The sabot 42 has an external diameter somewhat greater than that of bourrelet 41, and the peripheral portion of the sabot comprises la turning band which is adapted to be engraved by the riiiing inthe gun barrel to impart rotation to the projectile. The threads 40a are in such a direction that the rotation imparted to the sabot by the gun riliing acts to'tighten the sabot against the bourrelet 41.

It will be apparent that when the projectile is flred from a gun7 the centrifugal force incident to the rotation of the projectile causes the sabot 42 and the bourrelet 41 to break apart adjacent the radial cuts v43 and 41a, respectively, when the projectile emerges from the gun barrel, so that the core 40 continues its Hight Without the sabot and'bourrelet.

The projectile` shown in FIGS. 16 to Ztl/inclusive., comprises a subcalibercore 45 carrying on its rear end portion a ring 46 which is made of light weight material, such as fiber. The ring 46 may be cemented or otherwise secured on the core and is adapted to lit tightly into a suitable cartridge case (not shown) for containing the propellant powder, the ring having a circumferential groove 46a in its peripheral portion into which part of thercase may be crimped. A plurality of longitudinal saw cuts 47 radiate from the inner surface of the ring and partially segment the ring to provide weakened zones.

In front of the ring 46, the core is provided with an annular groove 49 into which a plurality of steel segments 50 are closely fitted to form a sabot projecting radially from the cylindrical surface of the core. The sabot segments 50 are held closely together in the groove 49 by a frangible turning band 51 made of copper, or the like, and secured on the peripheral portion of the sabot as shown at .52. The front face of the sabot 50 is inclined rearwardly from the leading edge of the groove 49. A sealing disc 53 engages the rear face of the projecting portion of sabot 50 in spaced relation to the ring 46. Y

A substantially full caliber bourrelet 55 made of fiber or other lightweight material is fitted closely on the cylindrical portion of the core in front of the sabot 50, the rear end of the bourrelet being formed to fit closely against the inclined sabot surface 50a and the turning band 51. The bourrelet 55 is sleeve-like in form and has longitudinal saw cuts 56 radiating from its inner surface but terminating short of its outer surface to provide weakened zones.

The turning band 51 has an external diameter somewhat greater than that of the bourrelet 55 and the ring 46 and is engraved by the riiling in the gun barrel to impart rotation to the projectile when the latter is fired from the gun.

Whenthe projectile emerges from the gun muzzle, the centrifugal force due to rotation of the projectile causes the turning band 51, ring 46 and bourrelet 55 Ato break apart so that thesemembers and the sabot 50 are released from the core. The sealing disc 53 is then moved 0E the rear end of the core by the air pressure on the disc, and the core continues its ight without the drag which would normally be imposed by the parts mounted on it. Y

It will be apparent that in the several illustrated embodiments of the new projectile, the bourrelet is of a sleevelike form held in place by its close t on the core and by engagement of its rear end with the front face of the sabot which is positively secured to the core. Because of the form and support of the bourrelet, the latter may be made of relatively Weak and light-weight material, whereby the ratio of the mass of the sabot and bourrelet to the mass of the core may be maintained relatively low. Also, with the new construction the bourrelet may be easily manufactured and mounted on the core, without the use of postive securing means other than the sabot. By reason of the interengagement of the radially projecting portions of the sabot and bourrelet, these members provide mutual lateral support.

While we have given several examples of light-weight material which may be used in the manufacture of the discardable parts mounted on the core, it is to be understood that other light-weight materials may be used, and in the following claims the term plastic is intended to include other equivalent light-weight materials of a density substantially less than that of the core material.

We claim:

1. In a subcaliber sabot-projectile having a metal subcaliber core, a sabot mounted on the core and positively secured thereto, the sabot projecting radially from the core a substantial distance for supporting and centering the core in a gun barrel, a turning band on the sabot, a substantially full caliber plastic bourrelet tted closely on the core in front of the sabot and engaged at its rear end with the front face of the projecting portion of the sabot, the bourrelet extending forwardly from the sabot for a distance substantially in excess of the sabot width, and a substantially full caliber plastic sleeve mounted on the core to the rear of the sabot and having an annular groove for receiving part of a shell case, said sleeve, bourrelet, sabot and band being releasable from the core by centrifugal force incident to rotation of the projectile when it emerges from the gun barrel.

2. A subcaliber projectile comprising a subcaliber core having a base, a segmented sabot mounted on the core adjacent to the base, a turning band surrounding the sabot to conne the segments, the contacting surfaces of lthe sabot and turning band being of interrupted contour to provide a mutual intertting, and a bourrelet firmly mounted on the core ahead of the sabot, abutting both the sabot and the turning band throughout the entire radial distance of the sabot and at least part of the turning band.

3. A subcaliber projectile comprising a cylindrical subcaliber core having a reduced portion, a segmental sabot on the reduced portion, said sabot extending beyond the annulus of the core and having interruptions along its peripheral surface, a turning band iitted on the sabot, having complemental interruptions tightly intertting those on the periphery of the sabot to bind the segments together, and a bourrelet rmly mounted on the annulus of the core, abutting the adjoining surface of the sabot and overlapping the dividing line of the interruptions to abut at least part of the turning band.

References Cited in the file of this patent UNITED STATES PATENTS 40,198 Staord Oct. 6, 1863 132,903 Dana Nov. l2, 1872 FOREIGN PATENTS 131,034 Great Britain Aug. 2l, 1919 46,057 Sweden Nov. 5, 1919 809,845 France Dec. 19, 1936 

